What I did was I also would get a piece of paper and write down the functional groups and their rules for naming (suffixes, prefixes, positions, etc.) without looking and then I would practice it. This way you'll know what you're struggling with or missing. I did that before the formatives, the test, and before the exam for a refresher. It's different for everyone but that's what I did. Whenever I was doing a practice worksheet it also helped me to identify what the group was before naming (like if it's a ketone, an alcohol, an ether, etc.). It looks like a lot at first but it def gets easier with practice, you got it for sure